Stopped at a gas station went to start the 08Fusion back up and had the security system light flash. The engine did not crank so I turned the key off and back on and it started fine and drove fine but the Check Engine light lit. I decided to get it checked at an auto parts store as none of the local Ford Service Departments were open. I left it running so the code wouldn't clear and the code came up as U0100. The guy said He could not clear it. I shut the car off and when I restarted the CE Light was not lit for the rest of the day (8 starts and a couple hundred miles driving.)To my knowledge, this is a factory setup. Was this just a fluke or could there be more trouble in my future with this? Thanks for your input.
Ford Fusion U0100 lost communication code
- Thread starter oilstudent24
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Have the battery tested, low voltage will do strange things, also suspect the pcm relay. Those relays have issues.
my wifes highlander was throwing up CEL's a month ago. autozone scanned it and came up as the bank 2 O2 sensor. possible causes were inadequate voltage. popped the hood, positive terminal was heavily corroded. replaced terminal and cleaned the post and applied anti corrosion gel. now we get no CEL and it starts quicker.
new cars are very sensitive to voltage irregularities. so in short, check battery, check serpentine belt. if all physically checks out, go to orriely or autozone and have them check the electrical system ( battery, alt, starter.) hope this helps. might save you some money not goin to the stealership.
new cars are very sensitive to voltage irregularities. so in short, check battery, check serpentine belt. if all physically checks out, go to orriely or autozone and have them check the electrical system ( battery, alt, starter.) hope this helps. might save you some money not goin to the stealership.
The Battery should be good. 4 months old with lots of highway driving, but will have them check the charging system again.
Since the light is no longer lit, will the code still be stored? Can they diagnose anything without the light being lit? Don't want to go there without a light on and they say scanned it no codes $100 please lol
im not sure about code memory, id think in a modern car it would be able to remember it.maybe a real mechanic on here can answer that
the terminals may not have been tightened properly. might check that. might call ford and see if there are any software upgrades available for your PCM ,ECM or TCM.
the terminals may not have been tightened properly. might check that. might call ford and see if there are any software upgrades available for your PCM ,ECM or TCM.
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You need to get this car to the dealer ASAP.
This code can be originating from the TCM or Digital instrument panel as well as the PCM itself, in either case you will need more than a code scanner to diagnose this.
If there is an intermittent communication issue it will only get worse and will most likely leave you stranded on the side of the road at some point.
By all means check the battery condition (even new batteries can fail) and clean the terminals but don't over tighten the terminals, just snug will do as over tightening can damage the case to post seal.
Trying to diagnose shorts, bad grounds, iffy connections on this system is nearly impossible unless its blatantly obvious without specialized equipment, even then it can be difficult.
This code can be originating from the TCM or Digital instrument panel as well as the PCM itself, in either case you will need more than a code scanner to diagnose this.
If there is an intermittent communication issue it will only get worse and will most likely leave you stranded on the side of the road at some point.
By all means check the battery condition (even new batteries can fail) and clean the terminals but don't over tighten the terminals, just snug will do as over tightening can damage the case to post seal.
Trying to diagnose shorts, bad grounds, iffy connections on this system is nearly impossible unless its blatantly obvious without specialized equipment, even then it can be difficult.
I wonder what the "U" is all about? I'm guessing that it is "user defined". Most codes that we're familiar with start with P, as in Pxxxx. As such, it's probably a Ford specific thing, until the user community can reverse engineer it. Keep us posted!
U0100
U= Undefined
0= Generic
1= Emission Management
0= Reserved
0= Reserved
U= Undefined
0= Generic
1= Emission Management
0= Reserved
0= Reserved
Could any of this be covered under an emmisions warranty
Originally Posted By: oilstudent24
Could any of this be covered under an emmisions warranty
depending on mileage it might be.
Ford also have C codes for Chassis and B codes for Body.
Could any of this be covered under an emmisions warranty
depending on mileage it might be.
Ford also have C codes for Chassis and B codes for Body.
48,XXX Miles and about 4 yrs since titled
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